In vivo screening of optical brighteners as UV protectants and their efficacy in enhancing the virulence of Madurai isolate of NPV of Amsacta albistriga (Walker) (Lepidoptera: Arctiidae)

In vivo screening of eight optical brigliteners as UV protectants For Madurai isolate of NPV of Amsacta albistriga (Walker) revealed that Ranipal BVN and 2B provided excellent protection (> 80% original activity remaining). The retention of viral activity ranged From 90.8 to 97.6 per cent and 83.4 to 95.4 per cent in various concentrations from 0.1 to 1.0 per cent for Ranipal BVN and 2B, respectively while it was only from 4.6 to 7.0 per cent in UV irradiated NPV for 60 min. Addition of the best UV protectant, Ranipal BVN along with phagostimulants (molasses and crude sugar) and inorganic substances (boric acid and urea) enhanced the virulence of A. albistriga NPV by reducing LT₅₀ besides causing the highest mortality.